Motor vehicle manufacturers plan the application of sensor systems, especially of image sensors, for monitoring the passenger compartment of a motor vehicle. The use of image sensors is provided for intelligent air bag control. Within the scope of intelligent air bag control, one task is the classification of seat occupancy in the motor vehicle, in order, for example, to prevent injuries in small children by the triggering of air bags in the case of reverse-mounted child seats. Other planning involves monitoring the position of body parts of the passengers, such as the head or the torso, and/or the seating attitude of the passengers with respect to the air bag by a so-called “out-of-position detection”, so as, in particular, to avoid injuries by too close a positioning of the head to the air bag module when the latter is triggered.
As an example, from PCT International Publication No. 01/60662, a method and a device are known for the detection of seat occupancy with the aid of a video sensor system and a foot space sensor system. It is proposed there to record the height of the head of a person occupying a seat using the video sensor system, to carry out, together with the foot space sensor system, a classification of the seat occupancy, and to control the air bag as a function of the seat occupancy. Any hints on a device and a method for determining calibration parameters of an image sensor of the video sensor system are missing from PCT International Publication No. 01/60662 01/60662.